High Concentrations Of Heavy Metals Research Articles

Effects of copper and cadmium on stream leaf decomposition: evidence from a microcosm study.

We seek to understand how copper and cadmium act on leaf litter decomposition by their effects on microbial conditioning and litter fragmentation by invertebrates. In this study, we evaluated, in an integrated manner, different biological elements responsible for functioning of streams. Thus, we performed a microcosm assay with different concentrations for the two metals and their combination, evaluating their effects on fungi sporulation rate, consumption rate by shredders, and, consequently, the leaf litter decomposition rates. Sporulation rates were affected by all copper concentrations tested 10 × = 16µg L-1 and 25 × = 40µg L-1) but significantly reduced only at the highest concentration of cadmium (25 × = 22.5µg L-1). Increased copper and cadmium concentrations reduced the consumption of leaf litter by Phylloicus at 60%. The concentrations (10 × and 25 ×) of both metals resulted in a reduction in decomposition rates. When combined, copper and cadmium negatively affected microbial conditioning, consumption by shredders, and leaf litter decomposition. Increases in concentrations of copper and cadmium directly affected organic matter decomposition in aquatic environments. Thus, the presence of a high concentration of heavy metals in aquatic environments alters the functioning of ecosystems. As trace-elements occur in a combined manner in environments, our results show that the combined effects of different metals potentiate the negative effects on ecosystem processes.

Evaluation of Groundwater Quality. Case Study: Seini City, Maramureș County, Romania

"In the present study, in was investigated the groundwater quality from several private wells located in Seini city, Maramureș County (northwestern part of Romania). The investigated quality parameters were pH, redox potential, electrical conductivity, total dissolved solids, salinity, dissolved ions and heavy metals. The analysis showed that some of the investigated wells had a high content of nitrate, ammonium, and heavy metals. The continuous consumption of water from these sources can be a real threat for consumers’ health. The inhabitants should limit as much as possible the usage of water from these wells for drinking purposes and they should use the water from the local distribution network. Keywords: ground water quality, drinking water, chemical quality parameters"

Influence of Enriched Urease Producing Bacteria from Leachate and Restaurant Wastewater on Heavy Metal Removal

The escalation of heavy metal pollution in natural ecosystems due to industrialization presents a critical environmental concern, endangering the well-being of living organisms. Microbially Induced Carbonate Precipitation (MICP) technology, an emerging innovation, has gained attention from the scientific community for its potential in biocementation and bioremediation applications. However, a substantial gap in understanding exists regarding the utilization of ureolytic microbial strains from waste sources capable of effectively immobilizing high concentrations of heavy metals. This study endeavors to explore the latent potential of indigenous ureolytic bacteria derived from leachate and restaurant wastewater, possessing bioremediation capabilities for heavy metal immobilization. The investigation includes microbial screening, physiological characterization of ureolytic bacteria, assessment of their tolerance levels, and evaluation of heavy metal removal efficacy through Atomic Absorption Spectrophotometry (AAS) analysis. Notably, the results reveal that ureolytic bacteria from restaurant wastewater are more tolerant to Cd2+ concentrations compared to their leachate counterparts, manifesting optimum conductivity, pH, and optical density (OD). More so, AAS analysis demonstrates the restaurant wastewater-derived sample's remarkable proficiency in Cd2+ removal, achieving a substantial 95% removal rate, significantly outperforming the leachate wastewater sample's removal rate of 53%.

Low abundance and high patchiness of decapod fauna sampled with van Veen grab on the West African continental margin (Gulf of Guinea, Ghana)

Sixty morphospecies of Decapoda (Malacostraca: Crustacea) representing 34 families were recorded in the material collected in 2012 from 265 van Veen grab (0.1 m2) samples, from the nine transects distributed along the coast of Ghana in the 25–1000 m depth range. The examined material was dominated by the Diogenidae, Panopeidae, Leucosiidae, Pilumnidae and Xanthidae families. Species accumulation curves showed undersampling of the studied area and a large number of the morphospecies comprised singletons and doubletons. Panopeus africanus was the most frequent morphospecies in the analysed material (9.1% of all samples). We observed a substantial decrease of diversity (Shannon Index) and abundance along a depth gradient. Species richness also decreased with depth, starting from the highest number of morphospecies ‒ 38 at 25 m depth, then 33 at 50 m, 17 at 100 m, 11 at 250 m, 8 at 500 m and ending with 1 morphospecies at 1000 m bottom depth. Higher diversity was observed on the continental shelf (25–250 m – 57 morphospecies), while on the slope (500–1000 m) only eight morphospecies were recorded. Numerous factors of natural and anthropogenic origin may affect decapod communities on the coast of Ghana. Since our material was collected using a sampler collecting material at a very small scale, the observed patterns might be affected by the sampling method.

Content of proline and heavy metals in beekeeping prod ucts of different agro-ecological conditions of Ukraine

The production of beekeeping plays a crucial role in the population's nutrition. Bees yield valuable dietary products, such as honey, and provide raw materials for the food industry, such as beeswax. In addition to these primary products, bees produce royal jelly, flower pollen, propolis, homogenate of drone larvae, and bee venom. In regions with advanced agriculture, bees are utilized to pollinate entomophilous crops. Bee pollination enhances plants' similarity and yield, improving agricultural product quality. Honey-producing bees consume pollen, with flower pollen from nectariferous plants serving as the raw material, followed by bee bread, which is brought into the hive. However, the agroclimatic conditions in various regions of Ukraine only sometimes provide sufficient diversity of nectariferous plants to adequately meet the protein and mineral nutrition needs of bees. Minerals in animal organisms perform crucial functions, providing structural integrity to the skeleton and constituting essential components of organic compounds, vitamins, and enzymatic systems. In contemporary animal production, heavy metals threaten the health of both humans and animals. According to established norms, many of these metals are vital elements that must be included in the animal diet. Inadequate or excessive levels of these elements in the animal body can lead to the inactivation of enzymatic systems, impaired reproduction, decreased productivity, and reduced product quality. Heavy metals, especially mercury, lead, chromium, and nickel, are more dangerous toxins in living organisms at elevated concentrations. The chemical composition of living organisms and their impact on geochemical processes varies. To ensure normal vitality and the production of high-quality animal products, animals must be provided with a balanced diet and an optimal content of minerals that contribute to increased productivity and production efficiency. Therefore, studying the content of heavy metals such as iron, copper, zinc, lead, cobalt, and cadmium in honey obtained under different agroecological conditions in Ukraine is of significant economic importance. The research results indicate that the content of heavy metals in honey from the Western region, except iron and zinc, was higher than in the Southern region. Specifically, for copper, this advantage amounted to 86.725 mg/kg or 1.4 times, for lead – 50.203 mg/kg or 2.8 times, for cobalt – 57.865 mg/kg or 24.2 times, and for cadmium – 4.663 mg/kg or 2.7 times. Honey from the Southern region had a higher iron content of 0.237 mg/kg or 1.1 times, and zinc by 4.412 mg/kg or 5.5 times compared to honey from the Western region. Based on the obtained data, it is established that honey from the Western region has a higher content of heavy metals than honey from the Southern region, indicating more significant contamination of nectariferous plants in the Western region.

The impact of anthropogenic transformation of urban soils on ectomycorrhizal fungal communities associated with silver birch (Betula pendula Roth.) growth in natural versus urban soils

Betula pendula Roth. is considered a pioneering plant species important for urban ecosystems. Based on the sequencing of fungal ITS, we characterized the ectomycorrhizal (ECM) communities of twenty silver birch trees growing in a contaminated, highly anthropo-pressured urban environment and in a natural reserve site. We analysed chemical properties of each tree soil samples, focusing on effects of anthropogenic transformation. Three effects of urbanization: high heavy metal content, increased salinity and soil alkalinity, were highly correlated. The examined trees were divided into two forest and two urban clusters according to the level of anthropogenic soil change. The effect of soil transformation on the ECM communities was studied, with the assumption that stronger urban transformation leads to lower ECM vitality and diversity. The results of the study did not confirm the above hypothesis. The ECM colonization was above 80% in all clusters, but the forest clusters had significantly higher share of vital non-ECM root tips than the urban ones. Eleven mycorrhizal fungal species were identified varying from seven to nine and with seven species observed in the most contaminated urban plot. However, the lowest Shannon species diversity index was found in the most natural forest cluster. In conclusion, our findings demonstrate no significant negative effect of the urban stresses on the ECM communities of silver birch suggesting that both forest and urban trees have the potential to generate a similar set of ECM taxa.

Comparison of leaching behaviour of heavy metals from sediments sampled in sewer systems - environmental and public health aspect.

The article analyzes the content of heavy metals and standard physical as well as chemical pollution indicators in different types of sediments from stormwater, combined sewer and sanitary sewer systems. Nickel, lead, chromium, copper, zinc and cadmium, as well as standard physical and chemical pollution indicators, were determined in sewage sediments. Aqueous extracts of sediments samples, taken from storm water sewer inlet sediments traps, storm sewers, sanitary sewers and combined sewers, were prepared in accordance with PN-EN 12457-2:2006. After mineralization, the concentrations of the metals: nickel, lead, chromium, copper, zinc and cadmium in the extracts were determined using the inductively coupled plasma emission spectroscopy technique. The results were analyzed with a non-metric multidimensional scaling algorithm. The heavy metal content was variable depending on the sediments collection site. The heavy metals nickel, lead, chromium, copper, zinc and cadmium were found in the sediments from stormwater inlets, storm sewer and sanitary sewer channels, with variability in the concentration of individual metals. The sediments from the flushing of sanitary sewers and combined sewers did not contain cadmium. The content of heavy metals in sediments varied depending on the sampling location and type of sewer system, indicating the need for detailed monitoring to identify the sources of emissions. Sediments from stormwater sewers have higher concentrations of heavy metals, with those from sewer inlets showing zinc concentrations exceeding regulatory limits, highlighting the variability and potential environmental impact of different sewer systems.

Effectiveness of depuration with zeolite stone filter to reduce levels of heavy metal lead (Pb) in the feather shell (Anadara antiquata)

Lead toxicity in humans causes neurological disorders, bone metabolism disorders, kidney damage, and impaired liver function. Feather shells that live in marine waters with high Pb heavy metal content can be exposed to these heavy metals, posing a risk to humans who eat shellfish. Depuration is one method that can reduce the Pb content in the body of the feather shell. The depuration process is influenced by several factors, including the length of the depuration and the filter used. This study aims to determine the effective depuration time to reduce the Pb content in feather shells (Anadara antiquata) using zeolite as a filter. This study applied the Latin Square Design (RSBL) method as a research design consisting of four treatments with four replications. The duration of the depuration treatment was 0 hours (P0), 24 hours (P1), 48 hours (P2), and 72 hours (P3). The effectiveness of the depuration of shells using a zeolite filter can be seen in the reduced Pb content in shellfish. The depuration process for 24 hours showed an effective depuration time with a reduction rate of Pb of 1.095 ± 0.05 mg/kg.

Mineral Weathering and Metal Leaching under Meteoric Conditions in F-(Ba-Pb-Zn) Mining Waste of Hammam Zriba (NE Tunisia)

Mining waste is an obvious source of environmental pollution due to the presence of heavy metals, which can contaminate soils, water resources, sediments, air, and people living nearby. The F-(Ba-Pb-Zn) deposit of Hammam Zriba located in northeast Tunisia, 8 km southeast of Zaghouan was intensively exploited from 1970 to 1992. More than 250,000 m3 of flotation tailings were produced and stored in the open air in three dumps without any measure of environmental protection. Thus, in this paper, mineralogical and chemical characterization, especially the sulfide and carbonate phases, were carried out to evaluate the potential for acid mining drainage (AMD) and metal leaching (ML). Conventional analytical methods (XRD, XRF, SEM) have revealed that this mining waste contains on average 34.8% barite–celestine series, 26.6% calcite, 23% quartz, 6.3% anglesite, 4.8% fluorite, 2.1% pyrite, and 0.4% sphalerite. The content of sulfides is less important. The tailing leaching tests (AFNOR NFX 31-210 standard) did not generate acidic leachate (pH: 8.3). The acidity produced by sulfide oxidation was neutralized by calcite present in abundance. Furthermore, the leaching tests yielded leachates with high concentrations of heavy metals, above the authorized thresholds. This high mobilization rate in potential toxic elements (PTE) represents a contamination risk for the environment.

The occurrence of heavy metals and antimicrobials in sewage sludge and their predicted risk to soil — Is there anything to fear?

The study assessed the occurrence of legally-monitored heavy metals and unmonitored antimicrobials in sludge from small, medium, large and very large municipal wastewater treatment plants (WWTPs), and the predicted environmental risk and risk of resistance selection associated with sludge administration to soil. The temporal variations of the studied compounds in sludge and associated risks to soil were determined by sampling over a year.Although the highest concentrations of heavy metals were noted in sludge from the largest WWTP, i.e. from 1.50 mg/kg (mean 1.61 mg/kg) for Cd to 2188 mg/kg (mean 1332 mg/kg) for Zn, the obtained values only reached a few percent of the legal limits. The same WWTP also demonstrated lower concentrations of antimicrobials compared to the smaller ones. The highest concentrations of antimicrobials, ranging from 24.04 μg/kg for trimethoprim to 900.24 μg/kg for tetracycline, were found in the small and medium WWTPs. However, due to lack of regulations at the national and EU levels, the results cannot be compared with legal limits. Principal Component Analysis (PCA), cluster and heatmap analysis separated samples according to WWTP size. Small WWTP demonstrated correlation with antimicrobials (tetracycline, trimethoprim, clindamycin, ciprofloxacin and ofloxacin), while the large and very large WWTP revealed correlations with heavy metals (Cu and Cr).The obtained environmental risk quotients confirmed that the heavy metals did not present a threat, measured either as individual risk quotients (RQenv), cumulative risk (RQcumulative) or risk of mixture of heavy metals (RQmix-metals). In the case of antimicrobials, only tetracycline demonstrated moderate RQenv, RQcumulative and RQmix-antimicrobials in the small WWTP sludge, with values of 0.1 to 1. Our findings highlight the importance of monitoring sewage sludge before soil application, especially from small WWTPs, to reduce the potential environmental impact of antimicrobials. They also confirm our previous data regarding the environmental risk associated with various toxic compounds, including emerging contaminants, in the sludge from small WWTPs.

In vitro toxicity of fine and coarse particulate matter on the skin, ocular and lung microphysiological cell-culture systems

Particulate matter (PM) has been associated with adverse effects on human health, causing allergies, skin and eye irritation and corrosion, respiratory tract irritation, headaches, bronchoconstriction, cardiopulmonary diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung cancer, reproductive problems, premature deaths, and epigenetic changes that lead to a wide variety of cancers, among other health conditions. The air quality in the Medellín - Colombia presents fluctuations that oscillate between the maximum permissible levels established at the national level and by the WHO, which represents a latent risk to people's health. Although important efforts have been made to quantify the different levels of pollution and administrative measures have been established to mitigate air pollution, little research work has been done to establish the relationship between these levels of pollutants and the effects on biological systems. The objective of the present research was to make a morphological and chemical characterization of particulate matter (PM) captured with a commercial air filter and a electrospun nanofiber membrane and evaluate the cytotoxicity of the each PM extracts in monolayer and co-culture models which recreate microphysiological systems of lung, skin and cornea and propose the possible cellular interactions that lead the cytotoxic response of the chemical compounds found in particulate matter in cities. The morphology and elemental chemical characterization were done with scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM – EDS). For the polycyclic aromatic hydrocarbons detection was made with a chromatographic method accoupled to mass spectrometer. Finally, the cytotoxicity was made in monolayers of A549, HEK001, and SIRC cell lines and microphysiological systems consisting of two-cell layer construct to resemble the interaction between fibroblast and epithelial cells that comprises naturally the corneal, skin and lung tissue. We performed three different cocultures models with BALB/3T3 clone A31 as a feeder layer, using porous Transwell® inserts in the in-contact and non-contact way. Monolayer and co-culture models were exposed to coarse and fine PM (1, 2, and 5 mg/mL) and the cell viability was evaluated at 24 h using an MTT assay. The electrospun nanofibers membranes demonstrates higher efficiency to capture PM with different sizes and high concentration of polycyclic aromatic hydrocarbons, heavy metals, and other chemical compounds responsible of many human diseases. Cytotoxic effects of MP were observed in all models at higher concentration; however, models exposed to fine PM exhibited a significant reduction in cell viability compared to those exposed to coarse PM. In addition, multilayer models are more resistant to PM exposure than monolayer models. Furthermore, the study indicated that, depending on the seeding strategy, different results might be observed: the non-contact model showed higher resistance to PM exposure than in-contact for SIRC and HEK001, but A549 monolayers showed the highest viability response. This study demonstrates the usefulness of applying co-culture models to assess environmental pollutant toxicity, in addition to being a potential alternative method to animal testing for risk assessment.

Chlorella pyrenoidosa as a potential bioremediator: Its tolerance and molecular responses to cadmium and lead

Heavy metal contamination negatively affects plants and animals in water as well as soils. Some microalgae can remove heavy metal contaminants from wastewater. The aim of this study was to screen green microalgae (GM) to identify those that tolerate high concentrations of toxic heavy metals in water as possible candidates for phytoremediation. Analyses of the tolerance, physiological parameters, ultrastructure, and transcriptomes of GM under Cd/Pb treatments were conducted. Compared with the other GM, Chlorella pyrenoidosa showed stronger tolerance to high concentrations of Cd/Pb. The reduced glutathione content and peroxidase activity were higher in C. pyrenoidosa than those in the other GM. Ultrastructural observations showed that, compared with other GM, C. pyrenoidosa had less damage to the cell surface and interior under Cd/Pb toxicity. Transcriptome analyses indicated that the “peroxisome” and “sulfur metabolism” pathways were enriched with differentially expressed genes under Cd/Pb treatments, and that CpSAT, CpSBP, CpKAT2, Cp2HPCL, CpACOX, CpACOX2, and CpACOX4, all of which encode antioxidant enzymes, were up-regulated under Cd/Pb treatments. These results show that C. pyrenoidosa has potential applications in the remediation of polluted water, and indicate that antioxidant enzymes contribute to Cd/Pb detoxification. These findings will be useful for producing algal strains for the purpose of bioremediation in water contamination.

Selective electrochemical reduction of mercury(II) from a simulated traditional gold mining wastewater contaminated with cyanide and heavy metals

In traditional gold mining (TGM), the wastewater discharges are contaminated with high concentrations of cyanide and heavy metals. Understanding the effects of different cyanide species on the electrochemical behavior of mercury(II) is critical for its removal from TGM wastewater. Herein, we evaluated mercury electroreduction using a model solution simulating a TGM wastewater containing Fe(II), Cu(I), Zn(II), Hg(II), and CN– ions. According to speciation diagrams, the predominant Hg(II) species is Hg(CN)42–. Cyclic voltammetry was used to study the reduction processes from the simulated TGM wastewater solution and to select the potential for the potentiostatic deposition process of mercury. Scanning electron microscopy with energy-dispersive X-ray spectroscopy was used to study the morphology and elemental composition of the deposits. The free cyanide (CN–) concentration affects the electrochemical behavior of the anionic cyanide complex Hg(CN)42– in addition to the chemical stability of 316 stainless steel under open circuit conditions. Voltammetry and electrochemical impedance spectroscopy measurements show that the 316 stainless steel electrode becomes more resistive when exposed to the simulated TGM wastewater solution due to a passive surface oxide, while the passive layer on the titanium electrode inhibits Hg(II) reduction.Graphical

PENGARUH PEMBERIAN TIMBAL (Pb) TERHADAP PERTUMBUHAN DUA VARIETAS LADA (Piper nigrum L)

The pepper (Piper nigrum L.) a plantation crop that widely cultivated farmers in Indonesia, especially in Bangka Belitung Islands. One of the challenges of pepper cultivation in Bangka Belitung is the reduction in land conversion caused by tin mining. Tin mining causes high levels heavy metal content. The heavy metal lead (Pb) is element that can influence its growth. Pb are will become an inhibitor of enzyme formation which inhibits plant metabolism and effect growh of pepper. The aim of this research to determine the effect of giving Pb to both varieties and determine which varieties are adaptive in planting media containing Pb. This research was carried out April to July, at Bangka Belitung University. The method used was experiment and the design used was a randomized (RAKF). Treatment consists 2 factors. The first factor is Petaling 1 cultivar and the Nyelungkup cultivar. The second factor, Pb concentration which consists of Pb concentration of 0 ppm, 100 ppm and 200 ppm. Data analysis used the F test (ANOVA) followed the Duncan’s Multiple Range Test (DMRT). The research results showed each cultivar did not have a real influence on the observed parameters. Aplication Pb concentrations 100 and 200 Ppm had effect on plant height, number of leaves, increasing number of shoots, leaf area and root length and root fresh weight. Nyelungkup cultivar is a cultivar that is better able to adapt to growing media contaminated with the heavy metal Pb better than Petaling 1.

KETERGANTUNGAN SEMAI JOHAR (Cassia siamea LAMK) TERHADAP FUNGI MIKORIZA ARBUSKULA PADA MEDIA TAILING TAMBANG EMAS

Tailings are the wastes resulting from mining activities in the amalgamation of mine ore from the ground, with extreme characteristics such as a sand-dominated texture, high Pb heavy metal content, very low availability of carbon and macro nutrients. Consequently, the plants may not able to grow well in the tailings. The application of Arbuscular Mycorrhyza Fungi (AMF) is expected to increase the ability of forest plant seedlings to grow and develop in tailings media. The research was carried out in a greenhouse using johar (Cassia siamea Lamk) seedlings which were inoculated with AMF inoculum: Glomus manihotis, Glomus etunicatum, and mix inoculan (mycofer), and planted in tailings media collected from Pongkor gold mine for 8 weeks. Johar seedlings were able to grow in tailings media and AMF colonization to the seedlings was observed. The compatibility of multi-species inoculum, mycofer, is higher than single AMF inoculum. The height, diameter and biomass growth of johar seedlings in tailings media significantly (p<0.05) increased with AMF inoculation. Johar seedlings have a high dependence on AMF, on tailings media, undicated by value of MIE > 50%, suggesting that the AMF application to johar is very necessary for revegetation activities in tailings media.

Simultaneous immobilization of multiple heavy metal(loid)s in contaminated water and alkaline soil inoculated Fe/Mn oxidizing bacterium

Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened. The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II) and Mn(II) by Pseudomonas taiwanensis (marked as P4) and Pseudomonas plecoglossicida (marked as G1) contains rich reactive oxygen functional groups, which play critical roles in the removal efficiency and immobilization of heavy metal(loid)s in co-contamination system. The isolated strains P4 and G1 can grow well in the following environments: pH 5-9, NaCl 0-4%, and temperature 20-30°C. The removal efficiencies of Fe, Pb, As, Zn, Cd, Cu, and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system (the initial concentrations of heavy metal(loid) were 1 mg/L), approximately reaching 96%, 92%, 85%, 67%, 70%, 54% and 15%, respectively. The exchangeable and carbonate bound As, Cd, Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil, thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s. This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.

Induced and natural moss soil crusts accelerate the C, N, and P cycles of Pb[sbnd]Zn tailings

Nutrient deficiency is the primary obstacle in tailing ecological restoration besides high heavy metal content. Biological soil crusts (BSCs) are known for their C and N fixation capabilities and play a crucial role in soil P cycle. BSCs are widespread in tailings and provide a potential ecological restoration approach. In 2022, we carried out an on-site restoration on a PbZn tailing pond in Yunnan Province, China. BSCs were propagated by natural moss crust fragment inoculation. The induced moss crusts (IMCs) were monitored at 0, 45, 90, and 135 days and compared with natural moss crusts (NMCs). The chlorophyll-a content and abundance of biotic organisms increased over time, reaching a peak at 135 days and surpassing that of NMCs. Moss crusts increased the content of C, N, and P nutrients and enzyme activities in the 0.5 cm surface soil. They also reduced the DTPA-extractable Pb content. Moss crusts significantly increased the content of fulvic/humic and protein-like/polyphenol substances, thereby raising the humic index of soil dissolved organic matter (especially NMCs). Furthermore, moss crusts also raised the abundance of nitrification (AOB and Nsr), denitrification (narG, napA, qnorB, and nosZ), and P-cycling (gcd, appA, phoC, phoA, and phoD) genes, especially IMCs after a 135-day inoculation. NMCs exhibited higher moss abundance measured via eukaryotic photoautotrophs. Moss crusts increased photosynthetic bacteria abundance (e.g., Leptolyngbya and Nostocales) and reduced the dominance of chemoautotrophic bacteria, especially the dark sulfide oxidation bacteria (Betaproteobacteriales). This trend was more pronounced in NMCs. Overall, IMCs can recover the functions of NMCs, and in some cases (e.g., abundance and diversity of biotic community, soil nutrient and N & P cycle genes), even surpass them. Our research provides new insights into the tailing ecological restoration.

Study of the Chemical Composition of Soil in the Natural-Technogenic Territory Aidarken

The article presents the results of an analysis of the content of microelements in the soils of the biogeochemical territory of Aidarken. Soil samples for analysis were taken from the top layer of soil cover (0-20 cm) at 3 points in the study area. Chemical analyzes for fertility elements (gross content of nitrogen, phosphorus and potassium, humus, absorption capacity, carbonate content, pH) and analysis for mechanical composition were carried out in the laboratory of the Republican Soil-Agrochemical Station of the Kyrgyzgiprozem State Research Institute under the Ministry of Agriculture and Mineral Resources of the Kyrgyz Republic. The soils of the studied areas belong to the following types: dark Turanian gray soils and mountain brown dry-steppe soils. Antimony, as an accompanying element of mercury, is above the maximum permissible concentration in all areas of the soil cover. High concentrations of individual heavy metals (Pb, Cu, Zn) were found in the tailings area.

Revealing the release and migration mechanism of heavy metals in typical carbonate tailings, East China

Refining the occurrence characteristics of tailings hazardous materials at source is of great importance for pollution management and ecological reclamation. However, the release and transport of heavy metals (HMs) from tailings under rainfall drenching in simulated real-world environments is less well portrayed, particularly highlighting the inherent neutralisation in tailings wastes under superimposed dynamic conditions. In this study, dynamic leaching columns simulating actual conditions were used to observe the release and transport of HMs from tailings under acid rainfall infiltration at spatial and temporal scales. The release rate of trace elements (e.g., As, Cr, Ni, Pb, Cd) is high. Neutralisation in the presence of carbonate rocks in the gangue reduces HMs release intensity from tailings with high heavy metal content, along with the precipitation of iron oxides and chromium-bearing minerals, etc. In addition, the vertical differentiation of HMs is more relevant to physical processes. In the absence of carbonate rocks in gangue, the lowest pH value is reached within 1.2 h after acid rain infiltrates the tailings. At the same time, Cu, Zn and Cd are released significantly from the minerals at the superficial level. The release of As(III) is mainly concentrated in the early and late stages of water-rock contact.

INFLUENCE OF HEAVY METALS ON THE BASIC PHYSIOLOGICAL PROCESSES OF CEREAL AND CEREAL PEGUM CULTURES

At the end of the 20th century, the constant growth of the population and the rapid development of production brought the situation with the state of the environment in many countries and regions of the world to the brink of an ecological crisis. One of the main factors in the degradation of the natural environment is its pollution by various pollutants, among which one of the main places is occupied by heavy metals. Given the above, it becomes clear the relevance of research on the impact of heavy metals on plants. Currently, they are actively held in many countries of the world. The article is aimed at studying the influence of heavy metals on the main physiological processes that occur in plants. The results of studies on the influence of heavy metals on the main physiological processes of grain and leguminous crops are presented. Based on the results of the analysis, it was proven that accumulating in large quantities in plants, heavy metals cause a negative impact on growth, development and other physiological processes. It was established that in the presence of large concentrations of these elements in cereal plants, a decrease in the height of the stem, a decrease in the number of internodes, a decrease in the accumulation of raw and dry biomass, as well as a decrease in the size of inflorescences are observed. The main reasons for the decrease in above-ground biomass productivity in plants are the negative impact of heavy metals on the growth and development of plants and the intensity of photosynthesis. Individual types of plant groups show different ability to accumulate heavy metals. The results of our own research established that in the presence of high concentrations of heavy metals, a decrease in the linear dimensions of leaves was observed in almost all types of plants with which research was conducted. All of the above testifies to various aspects of the effect of heavy metals on metabolic processes and the viability of plants. They affect various functional groups of biologically important substances of the body, displace essential metals from metal-containing complexes, and also generate active forms of oxygen, which often leads to the occurrence of an oxidative explosion in cells and even the death of plants.